Manganese-52 has a half-life of 6 days. how many days would a scientist have to wait for the radioactivity to be 12.5% the starting amount? 6 12 18 24

T = half life of manganese-52 = 6 days

t = time taken for the radioactivity to become 12.5% of starting amount

N₀ = initial amount of radioactivity

N = final amount =  12.5% of N₀ = 0.125 N₀

Using the equation

t = 18 days

the answer is a. at the equator

cant without the picture! ?